Apparatus and process for re-refining waste lubricating oil



(5, R. DUFFY April 9, 1935.

APPARATUS AND PROCESS FOR RE-REFINING WASTE LUBRICATING OIL Filed July21, 1935 Patented 9,1935 R f t I v UNITED STATES PATENT i APPARATUS ANDPRocEss FoR RE-REFIN N ING WASTE LUBRIGATING on.

George Richard Duffy, Medford, Mass assignor to Star Oil RefiningCorporation, Boston, Mass.,- a. corporation of Arizona a ApplicationJuly 21, 1933, Serial No. 681,480, 4ClaimS. (01. 196-16) This .inventionrelates to an apparatus and The still, furthermore, embodiesthereinafurnace process for re-refiningwaste lubricating oil. 7 fiprovided with a stack 5 within which is a'flue 6. The primary object ofthe invention is to pro- Any suitable form of fuel may beprovided forvide an improved apparatus and process by means the furnace 4 and thegases generated thereby 5 of which lubricating oils' which have beenconare conducted outwardly from said furnace 5 terminated and diluted byprevious use may be rethrough the flue 6. V V Y 7 refined and therebyreclaimed for subsequent lu- The mixture ofwaste' oil and clay 3 is fedinto 7 bricating use. t the container 2 through an inlet pipe LeadingAnother object of the invention is to provide from the container 2 atthe bottom thereof is an 10 an apparatus embodying therein an improved.outlet connection communicating with a plurality 10 means whereby themixture of impure oil and of pipes 9 suitably arranged as in a'coil,orcomclay, utilized as a bleaching agentin this process, municating onewithanother, and at i i may be agitated, circulated and preheated with-.the furnace d'beneath the container'2. The mixin the still to the endthat the productive'capacture of oil and clay is withdrawn from theconity of a still of a given size will be'increased by tainer 2 andforced through the pipes '9 by means 15 reason of its greaterheatingefiiciency; of a pump I Q, from which the mixture is forcedAnother objector the invention is'gto provide back mm the containerthrough a p p said an apparatus and process in whichflu'e gases mixturebeing dischar e below the level f the from the furnace of the still aredeoxidized and liquid within the container through a plurality utilizedto produce a reducing or-non-oxidizing oforifices i2 providedin the pipeH. 7 During this 20 'atmospherewithin the still, thereby preventing"circulation of themixture of oil and clay, the mix- "oxidation" of theoil and reducing'the amount of h is preheated as i pa s through t e p p"clay required to bleach the oil to a given color, and upon beingdischarged under pressure below said gases being first subjectedto atreatment the level of the liquid within the container 2,-a

;whereby.the o is removed th ref om d turbulence of themixture'iscreated within said 25 th n injected into the mixture of oil and lay cntai ves 3, l4 d I5 a ep v d i within-the still in a manner to increasethe agitacontrol the flow o liquid through the c ul t tion thereon I 7 pmeans. i I V j Another object of the invention is to rovide 2. During hp at f h st l a r du o means whereby the gases and products ofvaporihon-oxidizing atm p e e i m i t d t e 30 'zation generated withinthe' still may be disby utilizin 'waste flu g s s t at a generatedcharged therefrom and the 'condensable portions yffi Still- VT s d a p5' i ct d' 50 thereof liquefied-and discarded while the gaseous stack 5i a manner to o c te w h or non-condensable portions thereof are unitedflue 5 thereof. The p communicates With 3 with t e flue gases anddeoxidize din unison thereac o of w -kn wn m ,byvmcens '35 with anda'gain injected into the mixture of oil or which the waste flue gasesare withdrawn from "and clay, or by-passed from the oxidizing; agentfiue 5 compressed and forced through a p and carried directly back tothe stilL-if so de- I 8 i to a container I9 v e is a sired. r oxidizingagent such, for examplaraspyrogallio 40 still another object ofthe'invention is to reduce d o t d therein: This id i g agent 40 t mhazard which is usually r t i th is so confined within the container Isthat all type of apparatus. 9 i of the gases passing through saidcontainer will The invention consists in an appara us nd beiconductedinto closeassociationtherewith in process for re-refining wastelubricating oil as 'Such a manner a the O id g agent Swill set forth inthe following specification and parb o b th i y from h gases 45ticularly aspointed'out in the claims thereof. 'whi'ch remain, whichnow' contain o poz land The figure of-the drawing represents an ap- =N2are conducted throug a p p 0 d rectly into paratus embodying myinvention and by means of the container 2 where they a e di h r whichthe process 'of-this invention carried thro h a-p ura y' f r fi s int thmix- 60 out. E i V I ture of ciland. clay below the surface; of saidIn'the drawing, [represents a still embodying mixture. These gases aredischarged under therein a horizontally disposed cylindrical conpressureinto themixture of oil and clayand the V tainer' 2 for a mixture ofwaste lubricating oil I turbulence of said mixture isthereforeincreased; and clay 3 "mixed in suitable proportions and in A valve 22is provided for thepipe connection a manner well-known to those skilledin the art. iii-and valves '23 and are provided for the pipe)connections "I8 and 20 respectively. "A by-pass valve provides a meansof intercommunication between the pipe I8 and the pipe 20 and isprovided with a valve 26. By'opening the valve 25 and closing the valves23 and 24 the container I9 containing the deoxidizing agent may beeliminated from the system for reasons hereinafter to be more fullydisclosed. 7 1

During the operation of the still gases and vapors are generatedtherein. The vapors are formed because of the presence of water andgasoline contained withirrthe waste lubricating oil. It is necessary,therefore, to eliminate these vapors and for this purpose a pipe 21leads" from the top of the container 2 to a condenser 28 pro.- videdwith a coil 29 which-is exposed to a suitable cooling fluid, preferablywater, which is allowed to flow through the condensen said waterentering the condenser through an inlet pipe 30 and beingvdischargedtherefrom througha discharge pipe 3|. The coil 29 is connected by meansof a pipe 32 to a container 33 inwhichthe products of condensation arecollected and may be withdrawn therefrom through a pipe 34 having avalve '35 provided therein. The gases which enter "the container 33 arewithdrawn therefrom through a pipe 36 which communicates with the pipeconnection I6 leading to. the compressor IT. A valve 37 is provided forthe pipe connection 36. After themixture of waste lubricating oil andclay has been treated within the still for the necessary period, themixture is withdrawn from the container 2 and filtered by a mechanism asfol1ows:-Connected to thepipe II is a'pipe 38 which communicates with anagitator 39. A valve 40 is providedfor the pipe 38. As the "mixture ofoil and clay passes through the agita- Jtor 39a turbulence of saidmixtureis created therein by means of suitable paddle blades 4I providedupon a'shaft 42 rotated in any suitable manner by mechanism not shownbut well known to those skilled in the art. A pipe 43 connects thea'gitator 39 with-a cooler 44 provided with .a coil '45 therein throughwhich the mixture may flow, a1l the time being exposed to acoolingagent,

preferably water, which entersthe cooler through an inlet pipe 46 and isdischarged therefrom through a pipe 41. The cooler 44 is connected bymeans of a pipe 48 witha filter 49 of wellknown construction in whichisa suitable filtering medium"which is adapted to. separate from :theoilthe clay and all other foreign solid matter contained therein. The re-refined oil is withdrawn from the bottom of the filter through a pipe50having a valve 5| provided therein.

The general operation of the apparatushereinbefore specificallydescribed and by meansof which the process-of this invention is carriedout is as follows :-Waste lubricating oil; containing various'types offoreign matter, together with a certain amount of clay utilized as ableaching agent andwell known in oil refining processes, is fedintoJthelcontainer 2 and subjected toheat provided'by the furnace 4,said heat contacting 65 directly with the under side of the container.During'this'he'ating process the liquid within the container withdrawntherefrom by means of the pump I3 and forcedthroughthe pipes 9 which arelocated in the upper part of the fur.-

nace 14.. As the. liquid circulates through these f pipes it ispreheatedand finally forced back into 'the conta'iner 2 below theQlevelofuthe'liquid therein. in a manner to create a turbulence of said liquidwithin the container. The liquid is subjected to heatuntil thetemperature thereof ranges from 550F. to 650 F. During this heattreatingoperation waste flue gases generated within the furnace and conductedoutwardly therefrom through the flue 6 are utilized as a means formaintaining a reducing or non-oxidizing atmosphere within the container2 of the still. A portion of these waste flue gases which may contain002, O2 and N2 are withdrawn from the fine '5 and compressed by means ofthe compressor I1 and discharged into contact with the deoxidizing agentwhich is located within the container I9, which will absorb the free 02.The COzand N2 which remain are then forced into the container 2 anddischarged therein below the level of 'the' mixtureii in a manner tostill further increase 'theturbulence of said mixture. During thisoperation certain gases and vapors are created in the container 2 andare discharged therefrom through the pipe ZI'into the condenser 23 wherethe products of vaporization are liquefied and finally discharged intothe container 33 together warms gases which remain unliquefied. Theliquid can be drawn off at any time by manipulating the valve 35. Thegases are withdrawn from the container 33 by means of the compressor Hand are compressed and deox'idized of any further free O2 that may .becontained therein in unison with the flue gases by means of thedeoxidizing agent contained within the container 1 9,;being finallydischarged into a container 2 of the still as previously mentioned. a

After the'still has been in operation a predetermined length of tirneandtests disclose the fact that all of the free 02 which is in circulationhas been removed, the valve 22 is-operated to cut out entirely the flueI5, thereby preventing any more waste. fluef'gases from being placed incirculation; With all of the free 02 removed it is no long'ernecessaryto utilize the deoxidizing medium L .in the system and this istherefore. cut out by closing the valves Band. The valve '26 is thenopened and the gases and vaporsare thereafter withdrawn from the top ofthe container 2 andiafter being conducted through the condenser@ha'sbeen in operation for a predetermined period 5 ,at ,a" temperatureWhichmayrange between 550 .F. and 650 F. the valve I5 is closed and thevalve '40'ope'nedandthe liquid in a partly refined state is withdrawnfrom the container 2 of the still andforced by means of the pumplflsuccessively through the agitator 39, cooler 44 and filter 49andtheliguid is successively agitated, cooled to la certain extent,;andfiltered. During this filtering operation the clay and foreign solidmatter that still may be contained within the oil is removed fromsaid-oil. and the resulting re-refined oil may be withdrawn from thefilter by manipulating the valve 5I.

I By closing the valves I3 and I5 the preheating operation may be cutoutof the system at any time and if any leak appears in-the pipes 9 thevalve I3 may be actuatedto prevent'the oil-from entering these pipesand" subsequently leaking into the furnace. This constructionreduces'certainfire hazards that would otherwise exist; :By

reducing the amount of free 02 present the fire ,hazard is also.reduced. By utilizing waste flue gases and removing the freeOz therefromthe expense of'operating the, still is greatly reduced. By increasingboth the heating efliciencyand means to withdraw gases and vapors fromsaid oil velocity as said oil passes through the preheating tubes, areduction in the oil film thickness is obtained. The increased velocityof the oil through the tubes 9 reduces the possibility of the oilcracking, to a minimum.

While I have illustrated and described the waste flue gases utilized inthe process of this invention as being obtained from the flue leadingfrom the furnace to the still, it is evident that waste gases may beobtained from the stack or flue of any other furnaces that may belocated upon the premises adjacent to the'still without departing" fromthe spirit of this invention.

I claim:

1. An apparatus for re-refining waste lubricating oil comprising, incombination, a still adapted to contain a mixture of waste oil and clay,means to withdraw gases and vapors from said still and waste gases fromthe flue thereof, means to condense said vapors, means to deoxidize allof said gases, means to inject said deoxidized gases into the still,means to cut out the flue gases, means to cut out the deoxidizing means,means to return the gases withdrawn from the still back into said stillto maintain a non-oxidizing atmosphere therein, and means to filter saidmixture to remove the clay and other foreign matter therefrom.

2. An apparatus for re-refining waste lubricating oil comprising, incombination, a still adapted to contain a mixture of waste oil and clay,means to withdraw said mixture from said'still, preheat the mixture andagain discharge the mixture into the still below the level of the liquidtherein,

still and waste gases from the flue thereof, means to condense saidvapors, means to deoxidize all of said gases, means to' inject saiddeoxidized gasesinto the still, means to cut out the flue gases, meansto cut out the deoxidizing means, means to return the gases withdrawnfrom the still back into said still to maintain a non-oxidizingatmosphere therein, and means to filter said mixture to remove the clayand other foreign matter therefrom.

3. The process of re-refining waste lubricating oil which consists inapplying heat to a mixture of waste oil and clay, maintaining anon-oxidizing atmosphere within said mixture by passing hot waste fluegases through pyrogallic'acidand injecting the so-treated gases into themixture, and finally filtering the mixture to remove the clay and otherforeign particles therefrom.

'4. The process of re-refining waste lubricating oil which consists inapplying heat to a mixture of waste oil and clay, agitating said mixtureby withdrawing the same from the mass thereof, preheating it, andthenreturning it under pressure into the mass below the level thereof,maintaining a non-oxidizing atmosphere within the mixture by passing hotwaste flue gases through pyrogallic acid and inj cting the so-treatedgases,

while hot, into the mixture below the level thereof,

thereby increasing the turbulence of said mixture,

and finally filtering the mixture by removing the clay and other foreignmatter therefrom.

GEORGE RICHARD DUFFY.

